Method for desiccation



METHOD FOR DES ICGATION Filed NOV. 11 1920 HEATER I &

r QM 0Q- INVENTOR \MLFLEISHER.

ATTORNEY Patented Apr. l5, 192do mum orator...

WALTER L. 'FLEISER, OF NEW YORK, N. Y., ASSIGNOE '1'!) AMERICAN DRYmG PROO- ESSES, INC., 01 NEW YORK, N. Y., A CORPORATION OF NEW YORK.

METHOD FOR DESICGATION.

Application filed November 11, 1920. Serial No. 423,475.

. To all whom it may concern:

I, WALTERL. FLEIsHnR, a citizen of the United States, and a resident of the city,

county, and State of New York, have in- B vented a new and Improved Method forDesiccation, of which the following is a full,

clear, and exact description.

An object of my invention is to provide, a simple, inexpensive and eflicient method to for desiccating substances which can be sprayed.

In my method the drying or desiccating agent is an air current circulated to form substantially a hollow cylinder through 16 which the substance to be. desiccated is atomized so that the said substance passes through the hollow of the cylinder by entering laterally of the cylinder from the outside, and in a plane parallel to the elements 20 of the cylinder. The substance is atomized to enter substantially in-the form of a flat sheet. 7

In the accompanying drawing forming part of the application, Figure 1 represents as a diagrammatic, sectional view through a form of an apparatus suitable for my method and Figure 2 shows a vertical section through Figure 1 on line 2-2.

In all types of spray driers'a great dlfso ficulty is encountered in preventing the effluent air from carryin away therewith a large quantity of dust ormed by the small particles of the substance to be dried. Another difliculty is encountered in the spray 8e drying by the scale formation or case-hardenlng due to the contact of the hot dried air with the spray which produces particles having a hard shell and a soft core and which in consequence are not perfectly dried.

In my method of spray drying the arrangement is such that the air is so circulated that the hottest or dryest air contacts with the spray which has already been in contact with air not so hot or dry. In other words, the hottest or dryest air in my arrangement acts on particles of the spray,

partially dried. In consequence, the case hardening of the particles is prevented.

Further than that, the air that has already absorbed some of the moisture from the particles, as it approaches its exit strikes the spray nearer the nozzle, and'in consequence most of the dust in the etfluent air is washed down, thereby reducing considerably the dust in the eflluent air and increasing the size allel with the outlet opening. The row of the chamber 3.

of the particles formed within the spray drier.

Referring to the drawing, 3 is a desiccating chamber which has an elongated air inlet 4:, preferably extending across the entire chamber, (see Figure 2) and located preferably in proximity to the bottom of the chamber. The chamber 3 has an elongated air outlet 5 located on the same side and extending also throu h the entire width, of the chamber. T e said outlet 5 is near the inlet and the direct rise of the air from the inlet to the outlet is prevented by the velocity imparted to the air which causes the enterin layer of air to shape itself in a substantia ly hollow cylinder. The thickness of the air layer or wall of the air cylinder within the chamber 3 will vary from the inlet to the outlet due to the sudden expansion of the entering air layer and subsequent contrac tion when the air leaves the chamber 3 through the inlet 5. In consequence, the velocity of the air at the inlet and outlet is greater than at any point between the same, the minimum veloclty being in the thickest part of the layer forming the substantially cored cylinder.

A series of nozzles 6 are located within the chamber 3, on the same side with the inlet and the outlet and slightly above the outlet 5. The nozzles are arranged in a row extending substantially through theentire width of the chamber and preferably parnozzles is adapted, in combmation, to produce a flat sheet of the atomized substance I directed to intersect the hollow c linder formed by the drying air circulated t ugh See Fi re 1.) This s ray enters laterally. .o the cy 'nder and in a p ane parallel to the elements of the cylinder, or, in other words, the spray in form of a sheet enters the hollow cyllnder in a plane passing substantially parallel to the elements of the cylinder and 1n a direction. substantially at right angles to the elements of the cylinder. The air current is forced through the inlet Pinto the chamber 3, by a fan 7 which receives its air from a suitable heater 8, adapted to preheat the .air drawn by the fan 7 The nozzles 6, are fed from a tank 9, with the matter to be desiccated. A suitable air connection 10 is provided for the nozzles to form a desired spray within the chamber 3 110 or pressure nozzles may be used if so desired. The velocity of the spray formed within the chamber is such that the same should not be strong enough to pass entirely across the hollow or cored air cylinder formed by the d ing air within the chamber.

t must be understood that the hollow cylinder in cross section may be of any confi ration. As shown in the drawing it is slfii stantially of an oval shape. The gap that is shown between the inlet and the outlet in reality is very small due to the induction caused by the circulating current and eddies formed therein. The depression of the en.- tering air layer shown in Figurel is due to the eddies formed within the hollow of the cylinder. 7

From the drawing and the description it will be seen that the entering air attacks that part of the spray which has already been in 'contact with air previously in contact with the spray. In other words, the entering spray first comes in'contact with the air nearer to the outlet, that is with the air which is not as dry as the entering air,

' thereby preventing scale formation, thus in creasing the size of the dried particles.

In view of the fact that the spray passes across the air cylinder formed it may be said that theparticles of the spray are first treated with somewhat moist air and then with dry air, in consequence, increasing the efliciency of the spray drier and produclng a better commercial roduct and reducingJ the eigense of collecting the dust carried y the uent air.

As previously stated the velocity of the spray is such that the same cannot pass entirely acrossthe cylinder so that the entire spray will be under the action of the air current andthe dry particles formed collect Within the chamber at the bottom thereof where a suitable outlet 11 for the dried particles is provided. It will be noted that the spray intersects the air cylinder formed in p anes substantially parallel to the elements of the cylinder, or in other Words, arallel to the major axis of the cylinder i it has one, and the spray moves transversely of the elements of the cylinder.

It must be understood that although the description and drawing refer to an arran ement in which the air inlet and the air out st and the nozzles are disposed in a horizontal plane, the same can be disposed in any other plane provided the relation is such that the mlet, the outlet and the row of nozzles ar in parallel planes.

In other words, the air cylinder may be formed vertically in lieu of horizontally as shown. It is self evident that the relation between the inlet, the outlet and the row of nozzles will remain the same; that is to say, the airoutlet is located between the row of nozzles and the air inlet.

I claim:

1. A method of desiccation, which consists in creating an air current in the form of a cylinder havin a gap formed by the incoming and the e uent air, and forcing a spray of substance to be desiccated in the form of a sheet from the outside of the cylinder, the sheet of spray moving in a plane passing substantially parallel to the elements of the cylinder, and the direction of the spray being substantially at right angles to said elements.

-2. A method of desiccation which consists in creating an air current in the form of a hollow cylinder having a gap formed by the incoming and efiluent air currents, and forcing an atomized substance in the form of a sheet from the outside of the cylinder so that the said atomized substance moves in a lane parallel to the elements of the cylin er, and the direction of the spray being substantially at right angles to the elements of the said cylinder, said spray entering the said cylinder in proximity of the efiluent side of the gap.

WALTER L. FLEISHER. 

